Slow File Transfer on LAN with Large Files

Support
1

Hello,

I’m having issues with large files transfer speeds between two SyncThing clients on a LAN. I’m hitting about 1/6th of the transfer speed I can achieve when just copying the file from a windows file share. I’ve also verified this with Iperf3 testing.

For reference, I’m peaking about 130Mbit/s, when doing the test directly I can hit 600Mbit/s (writing to an SSD stripe set). I see the drive read from the source drive peaking at 10MB/s vrs over 100MB/s when copying directly.

I’m hoping someone has a tip, but for this, but I think this might be a bug. Probably this

2

I suspect your bottleneck is crypto or parallelism. Check CPU usage on both sides and in advanced settings try increasing number of pullers to like 150

3

Every bit of data sent by Syncthing is hashed and encrypted (which includes another layer of hashing), which is quite CPU intensive. It is not comparable to a regular file share or FTP, etc.

4

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